Triangle of opposition

In the system of Aristotelian logic, the triangle of opposition is a diagram representing the different ways in which each of the three propositions of the system is logically related ('opposed') to each of the others. The system is also useful in the analysis of syllogistic logic, serving to identify the allowed logical conversions from one type to another.

See also

• Logical cube
• Logical hexagon
• Octagon of Prophecies
• Square of opposition